204 ARCHIL 



coast, particularly in tho Canaries and several of the islands of the Archipelago. Its 

 colour is sometimes a light and sometimes a dark grey. 



There appears to bo good evidence for supposing that archil was known to the 

 Romans, and Beckmann is disposed to believe that tho ancient Greeks wore familiar 

 with this dye. This ingenious and industrious author gives the following account of 

 tho modern introduction of tho archil. 



' Among the oldest and principal Florentine families is that known under the name 

 of Oricellarii or Rucollarii, Ruscellai or Rucellai, several of whom have distinguished 

 themselves as statesmen and men of letters. This family is descended from a German 

 nobleman, named Forro or Frcderigo, who lived in tho beginning of tho 12th century. 

 One of his descendants, in tho year 1300, carried on a great trade in the Levant, by 

 which ho acquired considerable riches, and returning at length to Florence with his 

 fortune, first made known in Europe the art of dyeing with archil. It is said that a 

 little before his return from tho Levant, happening to make water on a rock covered 

 with this lichen, he observed that the plant, which was there called respio or respo, and in 

 Spain orciglia, acquired by the urine a purple colour, or, as others say, a red colour. 

 He, therefore, tried several experiments, and when he had brought to perfection tho 

 art of dyeing wool with this plant, he made it known at Florence, where ho alone 

 practised it for a considerable time, to tho great benefit of the state. From this 

 useful invention tho family received the name of Oricellarii, from which at last was 

 formed Rucollai.' History of Inventions. 



For more than a century Italy possessed the exclusive art of making archil, obtain- 

 ing tho lichens from the islands of the Mediterranean. Teneriffe furnished annually 

 500 quintals (of 110 Ibs. each) of lichen; the Canary Isles, 400; Fucrta Ventura, 

 300 ; Lancerot, 300 ; Gomera, 300 ; Isle of Ferro, 800. This business, in the islands 

 of Teneriffe and Canary, belonged to the Crown of Spain, and in 1730 brought in a 

 revenue of 1500 piastres. Tho farmers paid from 15 to 20 reals for tho right to gather 

 each quintal. 



Since 1402 the largest quantity of the lichens for the preparation of archil has been 

 obtained in the Canary Islands ; a smaller quantity has, however, been procured from 

 the Cape de Verde Islands. It is stated that the archil from the lichens of the latter 

 place dye wool of a deeper colour than the archil from the Canaries, but that the dye 

 is not so rich. The labour of collecting these lichens is very great, and men are ex- 

 posed to the greatest risks, being suspended by cords over the face of stupendous 

 cliffs. Upon the coasts of Spain, Scotland, and Ireland, the peasantry have for a very 

 long period used lichens for the purpose of dyeing red. 



The chemical constitution of archil was first investigated by M. Cocq (' Annales do 

 Chimie,' vol. Ixxxi.) ; and subsequently, yet more extensively, by Robiquet (' Annales 

 do Chimie,' vol. xlii. 2nd series). 



From the Variolaria, Robiquet obtained Orcine, by digesting the lichen in alcohol, 

 evaporating to dryness, dissolving the extract in water, concentrating the solution to 

 the thickness of a syrup, and setting it aside to crystallise. It forms, when quite pure, 

 colourless prisms, of a nauseous sweet taste, which fuse easily, and may bo sublimed 

 unaltered. Its formula is C U H 8 0* (C 7 H"O 2 ) ; when crystallised from its aqueous 

 solution it contains 5 Aq. 



If orcino be exposed to the combined action of air and ammonia, it is converted into 

 a crimson powder orceine, which is the most important ingredient in the archil of 

 commerce. Orceinc may be obtained by digesting dried archil in strong alcohol, 

 evaporating the solution in a water-bath to dryness, and treating it with ether as long as 

 anything is dissolved; it remains as a dark blood-red powder, being sparingly soluble 

 in water or other, but abiindantly in alcohol. Its formula is C M H'N0 8 (C'H'WO*). 



Orceine dissolves in alkaline liquors with a magnificent purple colour ; with metallic 

 oxides it forms lakes, also of rich purple of various shades. In contact with de- 

 oxidising agents, it combines with hydrogen as indigo does, and forms letic-orceino. 

 When bleached by chlorine, a yellow substance is formed, c/<for-orceine. 



Dr. Schunck, by an examination of several species of Lecanora, has proved that, 

 although tinder the influence of ammonia and of air, they iiltimately produce orceine, 

 these lichens do not contain orcino ready formed, but another body, Lecanorine, which, 

 tinder the influence of bases, acts as an acid, and is decomposed into orcine and car- 

 bonic acid. If lecanoric acid be dissolved in boiling alcohol, it unites with ether, 

 forming lecanoric ether, which crystallises beautifully in pearly scales. In the Roccella 

 tinctona and the Evcrnia prunastri erythric acid is found By tho oxidation of this 

 acid amarythrine or crythrinc bitter is formed. These substances have been carefully 

 examined by Schunck, Stenhouse, and Kane. The chemical history of these and some 

 other compounds is of great interest; but as they do not bear directly upon the 

 manufacture of archil, or its use in dyeing, further space cannot be devoted to their 

 consideration, 



